Valve monitoring for sensing the open or closed or both conditions of valves in a fire sprinkler installation has been known, for example, in U.S. Pat. Nos. 4,696,325, 4,967,792 and 5,031,660. Building regulations have been proposed to provide for monitoring of valves in a fire sprinkler installation so as to permit an alarm condition to be triggered if there is an attempt to turn off control valves that allow water to pass to sprinkler heads. The abovementioned prior patents relate to different aspects of valve monitoring and generally relate to valve monitoring to avoid attempts to override any alarm switches that may otherwise activate if a person were maliciously attempting to close the valves to prevent normal operation of the sprinkler system in the event of a fire.
Typically, such valves come with a gear box which can be operated manually to move a gate of the valve from a closed condition to an open condition and vice versa. Some gear boxes incorporate valve monitoring functions within these gear boxes to sense the open or closed condition of the valve, however, we have determined that there are deficiencies in existing valve monitoring techniques which allow the valve monitoring functions to be bypassed either for nefarious reasons or by tradespeople taking shortcuts during maintenance. In this respect, it is critical particularly for sprinkler systems be fully operational as even a partial closure of the valve can result in insufficient fluid flow to allow the sprinklers to operate effectively if there is a fire.